Motor starters are electromechanical devices that provide starting and stopping of electric motors by means of manual or automatic switches, and provide overload protection to the motor circuits. Motor starters are used wherever electric motors over a certain horsepower are operated. There are several types of starters including manual, magnetic, soft-starts, multi-speed, and full voltage types, among others. Some motor starters also have a reversing feature as well as features for torque control and jogging. Most also have standardized mounting configurations designated in NEMA sizes.
Motor Starter Styles and Types
Manual Motor Starters are used in so-called full voltage, across-the-line applications for small to medium sized single- and three-phase motors. Consisting of an on/off switch and an overload relay, a manual motor starters does not normally provide for disengagement of motor power in the event of power interruption, which can be beneficial for small pumps, fans, etc. as they will resume operating upon restoration of power. Manual motor starters with under-voltage protection provide a means of de-energizing the starter circuit after a power interruption and hence are used for conveyors, etc. where there is danger from an automatic restart to both equipment and personnel. Manual motor starters with under voltage protection are used on machine tools, woodworking equipment, etc. where safety requirements call for the motor to drop out after power failure.
Magnetic motor starters rely on electromagnets to close and hold contactors rather than the use of mechanical latching of on/off switches as used in manual starters. They are used in across-the-line applications and as reduced voltage starters for single- and three-phase motors. Magnetic motor starters using momentary-contact pilot devices (switches, relays, etc.) require a restart after a power loss or low voltage condition causes the contactor to drop off. Magnetic motor starters can also be wired to restart motors automatically if the application requires it, a remote pump, for example.
Combination starters are generally housed units that incorporate disconnects and short circuit protection (in the form of fuses or circuit breakers) together with the components of the motor starter. They can be designed as standalone units, but they are more commonly used as alternatives to separate starters, which offer fewer features. The layout of a combination motor starter is similar to that of a separate motor starter with the exception having an internal waterproof box at one corner of the device; this leads to one terminal inside the box being able to act as an overcurrent protective plug. These starting systems aren’t quite as versatile or flexible as conventional starters because they do not have their own regenerative capability and must rely on system help in order to function correctly.
Soft start technologies exist for various applications. Most prevalent of these is for large motor starting, also called full-voltage starting. In this way of starting, incandescent light bulb filaments are used or lamps that are connected to the load terminals in a circuit configuration. [→] This can be done with voltage from an external power source or from an inverter or a stepper motor controller that produces sufficient voltage to light up the filament in-line with the circuit powering it.
Applications and Industries
Motor starters are special purpose electrical devices designed to handle the high electrical current that motors draw momentarily when they are started from standstill while still protecting the motors from the excessive heat of overloads during normal operation. Starting current can be several times what the motor draws at its operating speed. If just a fuse or circuit breaker was used, that device would blow or trip with each start.
Motor starters provide the power to start heavy equipment such as large motors, generators, compressors and reciprocating engines. They are usually used with equipment that is started infrequently or which run continuously with few stops. Beyond there specs need to consider magnetic starters or even soft starters for special cases such as reversing or multi-speed services
A motor starter is a device used to start engines. They are usually used in smaller engines like lawn mowers, garden tractors, and other off-road equipment to speed up starting time. If you need a local starter, then a manual motor starter in an explosion proof motor starter may be able fulfill your requirement – and be much more economical. And If you’re having trouble installing a motor starter, or simply want to improve upon your existing installation, consider consulting with Solution Controls for assistance in wiring your motor starter to your motor or control system.